Creating Area Charts

Note: This is part of the Charts with Widgets Gallery example.

Image of a graph example

To create area charts, we need two QLineSeries instances. They are going to define the upper and lower boundary of the area.

 auto series0 = new QLineSeries;
 auto series1 = new QLineSeries;

We add data to both series and use the stream operator.

 *series0 << QPointF(1, 5) << QPointF(3, 7) << QPointF(7, 6) << QPointF(9, 7) << QPointF(12, 6)
          << QPointF(16, 7) << QPointF(18, 5);
 *series1 << QPointF(1, 3) << QPointF(3, 4) << QPointF(7, 3) << QPointF(8, 2) << QPointF(12, 3)
          << QPointF(16, 4) << QPointF(18, 3);

Now we create a QAreaSeries instance using two line series objects. We set the custom gradient fill and width of the outline.

 auto series = new QAreaSeries(series0, series1);
 series->setName("Batman");
 QPen pen(0x059605);
 pen.setWidth(3);
 series->setPen(pen);

 QLinearGradient gradient(QPointF(0, 0), QPointF(0, 1));
 gradient.setColorAt(0.0, 0x3cc63c);
 gradient.setColorAt(1.0, 0x26f626);
 gradient.setCoordinateMode(QGradient::ObjectBoundingMode);
 series->setBrush(gradient);

Last we create the QChartView instance, set the title, set anti-aliasing, and add the area series. We also create the default axes and specify the ranges on them.

 auto chart = new QChart;
 chart->addSeries(series);
 chart->setTitle("Simple Area Chart");
 chart->createDefaultAxes();
 chart->axes(Qt::Horizontal).first()->setRange(0, 20);
 chart->axes(Qt::Vertical).first()->setRange(0, 10);

The chart is ready to be shown.

 createDefaultChartView(chart);